Different uid 's on different machines ?

[ats2]

Hi,
I've met today something strange. I have a bunch of gentoo servers, and all of them have the same uid 's for basic accounts, like fcron et tcpdump, namely 101 and 102.
But I discovered that on two new servers, these uid's have been switched, which causes rather strange things when synching file between these boxes (more precisely virtual servers with a mysql account inside). When I rsync (with -avzH) these files from A to B, uid's are swapped so that mysql inside the virtual server has a wrong uid. Which prevents it launching correctly.

Funny, eh?

So I have two questions :
1) How come that these uid's are different on two new/freshly installed machines ?
2) Isn't there some sort of consistency for these important uids in time ? Will it happen again on other machines ?

Thanks for your help on that matter, rather important for me.

ATS2

[Sadako]

When you add a new user yourself, the uid's are assigned first come, first serverd, starting at 1001.

New users added by portage work excatly the same, only starting from 101 (albiet certain daemons are assigned specific UID's, such as sshd and mysql).

What you've encountered simply implies the daemons in question (fcron and tcpdump ?) were emerge in a different order on the two different boxes, leading to different UID's.

You can change this if you really want, unmerging, deleting the user, and then re-installing in the correct order on one box would be one way, or just user `usermod -u UID user`, playing a little musical chairs with it.

Either way you'll need to change the ownership of the files owned by the user, although the first method (re-emerging) will involve a little less work here (I'd go with the second though).
`find / -uid` will be of help here, and don't forget to have a look at the GID's too.

[ats2]

When you add a new user yourself, the uid's are assigned first come, first serverd, starting at 1001.

New users added by portage work excatly the same, only starting from 101 (albiet certain daemons are assigned specific UID's, such as sshd and mysql).

What you've encountered simply implies the daemons in question (fcron and tcpdump ?) were emerge in a different order on the two different boxes, leading to different UID's.

You can change this if you really want, unmerging, deleting the user, and then re-installing in the correct order on one box would be one way, or just user `usermod -u UID user`, playing a little musical chairs with it.

Either way you'll need to change the ownership of the files owned by the user, although the first method (re-emerging) will involve a little less work here (I'd go with the second though).
`find / -uid` will be of help here, and don't forget to have a look at the GID's too.

Thanks for the answer. I thought those uid's were fixed inside each distribution. I was wrong. Your explanation makes it clear.
Thx.

ATS2